Re: How do i get multiple Min() values?

B. Pym wrote:

HenHanna wrote:
 

 
How do i get multiple Min() values?
 
          e.g.      for   Y = (x-2)*(x-3)   for x in range(-10,10)
                                   the min Y is hit twice
 
 
print(  min( ((x-2)*(x-3),  (x, (x-2, x-3)))
                                           for x in range(-10,10) ) )
 
 
 
is this easy in Scheme(Gauche) ?

 
Gauche Scheme
 
(use gauche.collection) ;; fold2
 
(define (min-by fn lst)
  (if (null? lst)
    (values '() #f)
    (fold2
      (lambda (x best worth)
        (let ((score (fn x)))
          (cond ((< score worth) (values (list x) score))
                ((= score worth) (values (cons x best) worth))
                (#t (values best worth)))))
      (take lst 1) (fn (car lst))
      (cdr lst))))
 
(min-by (lambda(x) (* (- x 2) (- x 3))) (lrange -10 11))
 
  ===>
(3 2)
0

newLISP

(define (min-by fun lst)
  (let (accum '() best 0 score 0)
    (dolist (x lst)
      (setf score (fun x))
      (cond ((or (empty? accum) (< score best))
             (setf best score)
             (setf accum (list x)))
            ((= score best) (push x accum))))
    (list accum best)))

(min-by (fn(n) (- (abs (* 10 n)))) '(0 9 2 2 -9 3))
  ===>
((-9 9) -90)